Tag: Space exploration

Liquid water may flow on present-day Mars, the United States’ National Aeronautics and Space Administration (Nasa) announced on Monday.

Liquid water is necessary for life as we know it, and its discovery on Mars adds to the evidence that the red planet could support life. Carbon-based life exists on Earth because it is in the “Goldilocks Zone”: if Earth were closer to the Sun, water would evaporate; further away, the water would freeze. However, Nasa’s discovery of hydrated minerals means that there could be life on the fourth rock on from the Sun.

“Our quest on Mars has been to ‘follow the water’ in our search for life in the universe, and now we have convincing science that validates what we’ve long suspected,” John Grunsfeld, associate administrator of Nasa’s space mission directorate, said. “This is a significant development, as it appears to confirm that water – albeit briny – is flowing today on the surface of Mars.”

Nasa’s evidence resides in the intermittent dark streaks on the planet’s surface, smudges running down gullies and canyons. “These darkish streaks appear to ebb and flow over time,” Nasa said. “They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons.”

“Warm” for Mars is when the temperatures are above minus 23-degrees Celsius.

Using instruments on board Nasa’s Mars Reconnaissance Orbiter, which has been orbiting the planet since 2006, scientists detected hydrated minerals in these streaks. These substances form when minerals combine with water.

“The detection of hydrated salts on these slopes means that water plays a vital role in the formation of these streaks,” said the Georgia Institute of Technology’s Lujendra Ojha, who is lead author on the report of these findings, published in journal Nature Geoscience.

Ojha first noticed these intermittent streaks in 2010 when he was an undergraduate.

We have long known that Mars has water on it, but it is in the form of ice, rather than liquid water – the planet has two polar ice caps containing millions of cubic kilometres of frozen water. But it is also thought that the planet once had large quantities of liquid water, which moulded the ancient face of Mars.

“When most people talk about water on Mars, they’re usually talking about ancient water or frozen water,” Ojha said. “Now we know there’s more to the story.”

However, Nasa’s announcement has raised a number of interesting questions, with scientists from around the world questioning how it would be possible for liquid water to exist on the surface of the red planet.

Dr Philip Metzger – a planetary physicist who recently retired from Nasa’s Kennedy Space Centre and is now at the University of Central California – said on Twitter: “Water on Mars’ surface in the thin air (1% of Earth’s air density) should evaporate immediately. So how does it flow downhill, form gullies?”

Additionally, it is not known where the water comes from, or if there is life at or near the streak sites – and rovers cannot go there.

In response to a Reddit “Ask Me Anything”, initiated as part of the announcement, Nasa Jet Propulsion Laboratory’s Rich Zurek said: “Because liquid water appears to be present, these regions are considered special regions where we have to take extra precautions to prevent contamination by earth life.

“Our current rovers have not been sterilised to the degree needed to go to an area where liquid water may be present.”